1. Technical Field
This application relates to the field of computer storage devices, and more particularly to the field displaying information related to a plurality of storage devices coupled to a plurality of hosts in a storage area network.
2. Description of Related Art
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units (host adapters), disk drives, and disk interface units (disk adapters). Such storage devices are provided, for example, by EMC Corporation of Hopkinton, Mass. and disclosed in U.S. Pat. No. 5,206,939 to Yanai et al., U.S. Pat. No. 5,778,394 to Galtzur et al., U.S. Pat. No. 5,845,147 to Vishlitzky et al., and U.S. Pat. No. 5,857,208 to Ofek. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units. The logical disk units may or may nor correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data stored therein.
A large system may consist of a plurality of hosts, a plurality of storage devices, and a plurality of switches that direct data between the hosts and the storage devices. Such a system, called a storage area network (SAN), provides for certain efficiencies and optimizations when the storage devices and hosts are used together. However, it may be difficult to monitor and control the objects of the SAN. One solution to this is to use special software provided by EMC Corporation of Hopkinton, Mass. for monitoring and controlling the objects. The EMC software runs on one or more hosts to monitor the SAN. The software also includes agents, which are separate programs that collect data from each of the objects of the SAN and report back to the EMC software running on the one or more hosts. The agents gather SAN information that is stored as records in a database.
In some instances, the total amount of data corresponding to a particular system parameter may constitute thousands of records. When a user requests the data, the system fetches all of the records, even if the user is interested in viewing only a small percentage of the records. Systems exist which allow a user to fetch a percentage of records of a database. However, those systems also provide additional commands/functionality to allow a user to indicate which portion of the database is of interest. Accordingly, it would be useful to be able to obtain only those records in which a user is interested without having to add additional complexity to the system.